Pumps



Sept. 22, 1959 THOMAS ETAL 2,905,096

PUMPS Original Filed Dec. 30, 1955 INVENTOR. Oar/a I? T/Iamas BY Faber-fA. /'7/'// Dow QM.

A TTU/P/VEY United States Patent PUMPS David F. Thomas, St. Paul, andRobert A. Hill, Minue i apolis, Minn., assignors to Waterou's Company,.Rams'ey County, Minn., a corporation of Minnesota Original applicationDecember 30, 1955, Serial No. 556,718, now Patent No. 2,781,000, datedFebruary 12, 1957. Divided and this application February 8, 1957, SerialNo. 638,950

4 Claims. (Cl. 103-136) This invention relates to an improvement inpumps and deals particularly with a manner of balancing the rotorsthereof. While the structure is shown in conjunction with a foam pump,it will be understood that the same idea could be applied equally wellto the rotors of pumps, of different types.

Difiiculty is often experienced in balancing the rotors of pumps and thelike. While pumps which travel at a low rate of speed often need not bebalanced with great precision, the necessity for providing an accuratebalance of the rotors increases as the speed of rotation increases. Therotors are usually made by a casting process and it is a well known factthat castings made from the same patterns often vary materially inweight. After the rotors have been machined, they are usually balancedeither by grinding material from the heavy side of the casting or byadding material to lighter portions of the casting. Considerable time isconsumed in either grind 'ing or boring sufficient material away toprovide a reasonably accurate balance. Time is also consumed in weldingor otherwise weightingthe lighter side of the rotor and difliculty isalso experienced due to the fact that any material added must be appliedto the inner surface of the rotor (when the rotors are hollow) and theinner rotor surface is not readily accessible.

An object of the present invention resides in the provision of a rotorhaving a series of angularly spaced projections attached thereto along arelatively fragile web of connection. Each projection is possessed ofsubstantial weight. One or more rings of such projections may beprovided in axially spaced relation. In balancing the rotor, projectionson the heavier side of the rotor are broken or chipped oil, thusreducing the weight of this portion of the rotor. This operation iscontinued until suflicient weight has been removed to balance the rotor.

A feature of the present invention lies in the fact that the accuracy ofbalance which may be obtained depends upon the number of projectionsprovided and the size and weight of each projection. If an extremelyaccurate balance is required, a larger number of small projections ispreferred. However, if the accuracy of balance is not extremelycritical, a smaller number of larger projections may be employed. Whenthe rotor is almost in balance, the accuracy may be increased bygrinding or boring a relatively small amount of the metal away or byadding a small amount of weight to the lighter side of the casting. Byfollowing this procedure the time required for the balancing operationcan be very materially reduced. By the provision of two rings ofprojections, one at or near each end of the rotor, dynamic balancing maybe effected by selectively removing projections at either or both endsas necessary.

The present application is a division of our previously filedapplication for Foam Pump, Serial No. 556,718, now Patent No. 2,781,000,filed December 30, 1955.

In the drawings forming a part of the specification:

Figure 1 is a cross sectional view through a pump showing a typicalapplication of the invention.

Patented Sept. 22, 1959' Figure 2 is an end elevational view of therotor used in the pump of Figure 1.

Figure 3 is a cross sectional view through the rotor, the position ofthe section being indicated by the line 3530f Figure 2.

The pump shown in Figure 1 of the drawings is only typical of a type ofinstallation showing an embodiment of the present invention. The pump isshown as having an inlet manifold 10 which is provided with an inletopening 11 surrounded by a cylindrical screen 12 extending crosswise ofthe inlet. Fluid may enter the inlet 11 and must pass through the screen12 to enter the manifold. An adapter flange 13 is shown as secured tothe outer surface of the inlet manifold for attaching an inlet pipe tothe manifold.

Ascreen 14 is supported in the inlet manifold 10 above the level of theinlet 11. Air may enter the screen 14. As a result, in the particulararrangement illustrated air and liquid are mixed by operation of thepump rotor.

A rotor housing 15 is connected to the inlet manifold 10 by a passage16. The housing 15 is generally cylindrical in form and includes anoutlet 17 which is in angular relation to the inlet 16. A portion 19 ofthe housing adjoining the outlet passage 17 angles away from the rotorand ribs 20 bridge the portion 19 as well as the outlet opening 17 so asto guide the vanes of the pump in a manner which will be laterdescribed.

An outlet manifold 21 is provided with an attachment flange 22 whichattaches to the flange 23 encircling the outlet 17. The outlet manifold21 contains a series of spaced screens 24 through which the mixed airand liquid must pass on leaving the pump so as to fairly intermix theliquid and air to produce a foam. r V

' A rotor 25 is mounted upon a supporting shaft 26 extending through theends of the rotor casing 15. The shaft 26 is mounted eccentrically withrespect to the center of the housing 15 as is clearly indicated inFigure l. Therrotor 25 includes an outer cylindricalshell 27 and aconcentric hub 29, the shell and hub being connected by radiallyextending ribs 30. Each rib is radially slotted from the outer surfaceor outer shell 27 as indicated at 31. Thus the rotor comprises an outercylindrical shell, an inner hub, radially extending spokes, and radiallyextending grooves in the spokes designed to accommodate radiallyslidable vanes 32.

The rotor 25 is in close proximity to the inner surface of the housing15 at a point between the inlet 16 and the outlet 17 and the rotoroperates in a clockwise direction as viewed in Figure 1. Accordingly,the vanes 32 sliding along the inner surface of the outer casing 15 actto force fluid from the inlet 16 to the outlet 17. Thus, a mixture ofair and fluid are forced to the outlet and through the screens 24 to theoutlet manifold 21.

In the particular arrangement illustrated in the drawings, a series ofangularly spaced inwardly projecting teeth 33 or lugs are provided onthe inner surface of the outer shell 27 of a rotor 25 at each end of therotor. This arrangement is provided as in such a structure the teeth orlugs are readily accessible between the various spokes 30. A web 34extends from the hub 29 to the outer rim 27 and is provided withapertures 35 therethrough between the various spokes 30 so as to permitfluid to pass through the rotor in the event any fluid enters the rotorand to prevent the rotor from being urged in one direction or the otherby fluid under pressure which may enter the hollow rotor.

The teeth 33 or lugs are best formed as illustrated in Figures 2 and 3of the drawings. It will be noted that each tooth includes an enlargedinner portion or enlarged inner extremity 36 which is connected to theouter shell 27 by a relatively thin web 37 providing a relatively smallarea of connection. This web 37 is of sufficient thickness to hold thevarious teeth 33 in their properlocation under normal operatingconditions. However, the webs 37 are sufficiently thin to permit thevarious teeth 33 to be broken away from the outer shell 27 of the rotorwithout causing any injury .to the rotor itself. .lf-de sired,additional rows of teeth or lugs such as 33 may beprovided in axiallyspaced relation .to those illustrated at opposite ends .of the rotor.

When it is desired to balance the rotor, the rotor 'is mounted upon itsshaft 26 or upon a similar shaft and the rotor is either placed in adynamic and static balancing apparatus which is well known in the artorelse the shaft is placed in suitable 'free running bearings .andallowed to rotate to :a stop so that the heaviest .part of the rotorwill be lowermost. Thereafter, the heaviest part .of the rotor islightened by breaking voif .one or more of the teeth .33. These teeth orprojections are heavy enough to cause a material .difference in the.balance of the rotor. If the rotor is only slightly out of balance, theremoval of one such itooth33 may be .suflicient to substantially balancethe rotor. In any event, the rotor may be approximately balanced .by theremoval .of a desired number of such lugs or projections 33 from theheaviest vpart of the .rotor. If a finer or more accurate balance .isrequired, this may be accomplished by grinding away portions ofadjoining teeth or addinga slightamount of weight to the lighter side ofthe erotor. In any event, any .rnaterial difierence in Weight on-.opposite sides of the rotor may be approximately balanced by-theremoval of certain'of the =teeth.or-projections-.33 thus greatlyreducing the time necessary -.to balance the rotor. Stated otherwise,the rotor may be balanced to a pointwhere the "weight on one side of therotor-differs from the weight on the Opposite side thereof by less thanthe weight of one of the projections 33. Furthermore, by properlyspacing the teeth removed from the heaviest side of .theerotor, andbyremovingteeth ton opposite sides of the heaviest point of the rotor,even a more accurate balance may be obtained. By selectively removingteeth from rings at both ends of the rotor, dynamic balancing maybelaccomplished if desired.

In accordance with the patent statutes, we :have .ade

scribed the principles of construction and operation of our Improvementin Pumps, and while We have endeavored to set 'forth the bestembodiments thereof, we desire to have it understood that changes may bemade within the scope of the following claims without departing from thespirit of our invention.

We claim:

1. A readily balanced :rotor :for use in a vane pump includingarotorhousing havingan inlet and an outlet, said rotor "including a rotor bodyrotatably supported in said housing, radially slidable vanes supportedby said rotor body, a series of angularly spaced lugs on said rotor bodyand a thin web between said lugs and .said rotor "body whereby saidrotor may be balanced by removal'of certainof said lugs.

2. A readily balanced rotor for use in combination with rotary pumpincluding a housing, :said rotor including a rotor body rotatablysupported within said housing, .a series .of .angularly spacedprojections on .said rotor body, .said projections being connected .to.said .rotor body by .a relatively .thin web, whereby :selected,projections may be removed .for balancing the rotor .body.

, 3 .A readily balanced rotor for use in combination 1 with rotary pumpincluding a .housing, said rotor ineluding a .rotor ibody rotatablysupported within said housing, .a series-of angularly spaced projectionsonsaid rotor body, each .said projection comprising a relatively large-.extremity, and a relatively small area ofconnection between said:extremity .and said rotor .body, said area of .connection being-fracturable to permit ,removal of selected projections for the purposeof balancing the rotor-body. H

4. The structure .ofwzlaim 3 and in which .the projectionsaregarrangedinaxially spacedrows.

' References Cited .in .the .fileof .this patent UNITED :STATES PATENTSwmmm

